4.12 Functional Programming

Question 1

What is the Domain?

Answer 1

1) The Domain is the set from which the functions input values are chosen

Question 2

What is the Co-Domain?

Answer 2

1) The Co-Domain is the set from which the functions output values are chosen

Question 3

What type of object is a function?

Answer 3

1) A function is a first-class object

Question 4

What are the characteristics of a First-Class Object?

Answer 4

1) Appear in Expressions
2) Assigned to a variable
3) Assigned as arguments
4) Returned in function calls

Question 5

What is Function Application?

Answer 5

1) Function Application occurs when a function is applied to its arguments

Question 6

What is the Composition of Functions?

Answer 6

1) The combination of two functions to get a new function

Question 7

What is a High-Order Function?

Answer 7

1) A higher-order function takes a function as an argument or returns a function as a result or does both

Question 8

What is a Map?

Answer 8

1) A Map takes in two arguments as inputs
- A Function
- A List

2) The Function is applied to each item of the list to produce a function output with new list

Question 9

What is the result of the following:

Map (5) [2,5,7,8,9]

Answer 9

[10,25,35,40,45]

Question 10

What is a Filter?

Answer 10

1) A Filter takes in two arguments as inputs
- A predicate (to define a boolean condition)
- A-List

2) A Function is applied to each item in the list and it returns a new list of each item that matches the predicate

Question 11

What is the result of the following:

Filter (>6) [2,5,6,8,9]

Answer 11

[8,9]

Question 12

What is A Fold (Recursive function)

Answer 12

1) Applies a function to each item of a list to produce a single value
2) An initial value is also supplied which will be recursively combined with the next item and so on

Question 13

What is the result of the following:

Fold (+)0[2,3,4,5]

Answer 13

[2,5,9,14]

Question 14

How is a list represented?

Answer 14

1) A List is represented as a concatenation of a head and a tail

Question 15

How are the head and tail split up in a list?

Answer 15

[a,[b,c,d,e]]
a = head
b,c,d,e = tail of a list

Question 16

Can a list be empty?

Answer 16

Yes

Question 17

Explain what the following operation does?

tail(list)

Answer 17

Returns a new list containing all but the first element of the original list

Question 18

Explain what the following does?

head(list)

Answer 18

Returns the first element in a list

Question 19

Explain what the following does?

empty(list)

Answer 19

Returns True if a list is empty otherwise False

Question 20

Explain what the following does?

length(list)

Answer 20

Returns the number of elements in a list

Question 21

Explain what the following does?

‘ : ‘ list constructor

Answer 21

Adds the items to the beginning of a list

Question 22

Explain what the following does?

prepend

Answer 22

Adds an item to the start of the list

Question 23

Explain what the following does?

append

Answer 23

Adds an item to the end of the list

Question 24

What type of list is this?

[]

Answer 24

Empty List